Hold-over arrangement for refrigerant system evaporators



Aug- 15, 1939A o. u. zERK ET AL 2,169,332

HOLD-OVER ARRANGEMENT FOR REFRIGERANT SYSTEM EVAPORATORS 4 Sheets-Sheetl TH'QATTORNEYb 4 Aug. l5, 1939 Y o. u. zERK ET Al. 2,169,332

HOLD-OVER ARRANGEMENT FOR REFRIGERAN''l SYSTEM EVAPORATORS Tm? ATTORNEYSAug. l5, 1939 o. u. zr-:RK Er AL HOLD-OVER ARRANGEMENT FOR REFRIGERANTSYSTEM EVAPORATORS Filed July l, 1935 '4 Sheets-Sheet 3- l1g 15, 1939 o.U. ZERK ET AL. 2,169,332

HOLD-OVER ARBANGEMENT FOR REFRIGERANT SYSTEM EVAPURATORS Filed July l,1935 4 Sheets-Sheet 4 714m ATTORNEYS.

Psienadfmig. 15, 1939 UNITED STATES PATENT OFFICE Oscar U. Zerk andDaniel Roland Vanneman, Chicago, Ill.; said Vanneman assigner to saidZerk Application July 1, 1935, Serial No. 29,332

5 claims.

This invention relates to refrigeration systems, and more particularlyto refrigeration systems and apparatus adapted for use in connectionwith'automotive vehicles,

'I'he application of refrigeration to movingvehicles such as automotivepassenger vehicles, pre- -when the engine sents problems which dier fromthose encountered in stationary refrigeration systems due to theintermittent operation of the vehicle and the variations in. vehiclespeed. In small refrigeration systems of the compressor, condenser andevaporator type refrigeration will take place shortly after the vehicleengine has initially started and the refrigerating' eect should be'sufiicient to prevent spoilage of food containedS in the coolingcompartment. The evaporator for such a system may consist of a smallcoil placed in the cooling compartment, but such systems would eil'ectrefrigeration only during the period and correspondingly the com- Ypressoiwere in operation. In other words, re`

frigeration will be available only when the automotive vehicle is movingor the engine is running at a speed equivalent to a vehicle speed inexcess of twenty-five miles per hour.

If the system were non-operative for an hour or two, particularlyon warmsummer days, food placed in the cooling compartment would warm up veryrapidly and spoilage would quickly occur.

.To obviate such a condition and provide refrigeration when the systemis non-operative, requires the presence during the idle period of someheat absorbing means, such means being usually termed hold-overmaterial. 'I'hese materials have the capacity of giving up heat duringperiods when the refrigeration unit is in operation and absorbing heatduring non-operative periods of the system. A

We are familiar with various types of hold-over material such as thesolid type which has a low specific heat and can therefore give up orabsorb only small amounts of heat without rapid uctuatlonsof-temperature. Hold-over materials. that remain in a liquid state havehigher specific heat, but also pass through a wide temperature rangewhile giving up or absorbing relatively small quantities of heat.

We preferably employ mixtures of liquids and salts, which' have trueeutectic freezing points and which can be quickly brought to theireutectic freezing point is above that of the refrigerant temperature.

In a system continuously refrigerated, such hold-over materials arechanged from a liquid a solid state without change in temperatureproviding such freezing point with the removal of heat. Thus, when there'- frigeration system is non-operative due to the non-operation of thevehicle engine, these frozen hold-over mixtures begin to absorb heat ata constant temperature until such time that all .5 of the solid materialhas reverted to liquid form. Thus, several hours after refrigeration hasstopped, the compartment will remain cool.

Although the hold-over material when frozen Will be at a somewhat highertemperature than that of the refrigerant, it will be possible tomaintain almost as low a temperature within the cooling compartment whenthe compressor is non-operative as when the compressor is in operation.The temperature variations will be l only a few degrees and will beinsuilicient to cause spoilage of food contained in the coolingcompartment.

`It is an object of our invention,` therefore, to provide, in arefrigerant system-having an inter- 20 mittently operable refrigeratingunit and an evaporator, means for maintaining the evaporator temperaturesubstantially constant over relatively longA non-operable periods vofthe refrigerating unit.

Another-object of our invention is to provide, in a refrigerant systemof the compressor, condenser and evaporator type, hold-over material formaintaining the evaporator temperature substantially constant duringnon-operating periods 30A of the compressor'and which hold-over materialis so associated with the evaporator as to have a maximum eiiiciency inabsorbing and giving up heat with a minimum temperature iiuctuation. 35Another object of our invention is to provide a refrigerating system ofthe compressor, condenser and evaporator type including a refrigeratorchamber for the evaporator, wherein holdover material is associated withthe evaporator and means are provided for substantially .concurrentlyeffecting freezing of the hold-over material and cooling therefrigerator chamber.

Another object of our invention is to` provide a refrigerating system ofthe above type including a refrigerator cabinet, an evaporator disposedin the cabinet and adapted to have ice cubes formed therein, hold-overmaterial associated with the evaporator to maintain the evaporatorand'chamber at low temperatures 50 during non-operating periods of thesystem, and wherein means are provided for substantially concurrentlyfreezing the ice cubes, cooling the hold-over material, and cooling therefrigeration chamber.

Another object of our invention is to provide a refrigeration system ofthe above type including an evaporator cooled by refrigerant coils andhaving hold-over materials associated therewith, and wherein therefrigerant coils and hold-over materials are so located relative to theevaporator that there will be sufficient surface of the evaporator incontact with air circulating in the cooling compartment within which theevaporator is disposed to continue the refrigeration.

Another object of our invention is to provide a refrigerant cabinetincluding an evaporator having an improved hold-over arrangement wherebya refrigerating temperature is maintained by a eutectic mixtureassociated with the evaporator and supplementing the cooling effect ofice cubes or the like.

Other objects of my invention and the invention itself will becomeincreasingly apparent from a consideration of the following descriptionand drawings, wherein:

Fig. l is a front elevational view, partially in section, of a preferredembodiment of my invention showing a hold-over evaporator, arefrigeration passageway, ice cube tray, and hold-over compartment;

Fig. 2 is a fragmentary elevational view generally similar to Fig. 1illustrating a cover meansy for the tray in compressed position;

Fig. 3 is a vertical sectional view illustrating the evaporator,refrigerant passageway and holdover compartments of the embodiment ofFig. l;

Fig. 4 is a diagrammatic view showing a development of the refrigerantpassageway illustrated in Fig. 2 substantially in a common plane;

Fig. 5 is a side elevational View of the evaporator and associated partsillustrated in Fig. 1;

Fig. 6 is a vertical longitudinal sectional view showing a modificationof my invention; and,

Fig. 1 is a sectional view generally similar to Fig. 6 showing a furthermodification of my invention.

Referring now to the drawings, we have indicated generally at I asuitably insulated refrigerator cabinet having an open type U-shapedevaporator, generally indicated at II, suspended from the top of thecompartment.

The evaporator II preferably comprises a U- shaped inner stamping I2 ofsheet metal, an 1ntermediate generally U-shaped stamping I3 having itslateral walls spaced outwardly from the walls of inner stamping I2 andthe top portion Il and the end portion (not shown) bent inwardly tosealingly engage the inner stamping and form pockets therewith asindicated at I-I5. An outer stamping I6 is formed with a continuousgroove therein whereby upon the stamping I6 being shaped in U-form andsealingly engaged with the outer wall and base of intermediate stampingI3 along each side of the continuous groove, a continuous passagewaywill be formed adapted to have refrigerant passed therethrough in amanner to be later described.

The aforesaid stampings I2, I3 and I6 are preferably formed of sheetsteel faced with copper whereby all contacting surfaces may be weldinglysecured by clamping the stampings together and placing the stampings ina non-oxidizing furnace, such as a nitrogen furnace.

Cross straps I1 are secured in any suitable manner as by welding andserve to hold the evaporator and form the means for suspending theevaporator from the cooling compartment. The

cross straps I1 are perforated and screws I8 encased by suitableinsulating material I9 are projected through the perforations andthreadedly engage the compartment top.

The ice cube tray and its associated parts are as generally indicated at20 and are removably supported by the evaporator; but the details oftray 2U form no essential part of the present invention.

In our copending application Serial No. 29,333, filed July l, 1935, Wehave illustrated a refrigeratlng system adapted to automotive vehiclesof the compressor, evaporator and condenser type wherein a thermallyresponsive expansion valve controls the passage of condensed liquidrefrigerant from the condenser to the evaporator and wherein a secondvalve also thermally responsive controls the passage' of the refrigerantfluid from the evaporator to the suction side of the com- Dressor.

In operation, the expansion valve, indicated at 22, Fig. 1, is sealinglysecured to a fitting 23 sealed to the inlet portion of the groovedpassageway I6. The refrigerant passes from the expansion valve 22,through fitting 23 and through the interconnected passageways indicatedat 2l, 25, 26, 21, 28, 29, 3U, and 3l successively; from passageway 3I,the refrigerant passes through a tube 32 disposed at the rear of theevaporator downwardly to passageway 33 and thence successively throughpassageways '34, 35, 36, 31 and 38 to an outlet fitting 39 at the outletend of the passageway. The outlet connection 39 sealingly joins aconduit effecting passage of the refrigerant directly to the suctionside of the compressor or through the evaporator control valvepreviously mentioned.

The passage of the refrigerant through the evaporator in this manneracts to flood the coils with liquid refrigerant, giving the bestarrangement for refrigeration. A most important feature of the design isthe arrangement of the coils to first supply refrigerant freezing theice cubes disposed in tray 20 as will be clearly understood by referenceto Fig. 1 wherein it is noted that passageways 24, 25 and 26 throughwhich the refrigerant first passes substantially underlie the base oftray 20. Heat is absorbed by the refrigerant when traversing thepassageway from both the inner and external surfaces of the evaporatorportion forming the passageway, as previously explained the heatabsorption from the inner surfaces freezing the ice cubes in tray 20 andat the same time the heat absorption at the opposite or outer side iscooling the air adjacent thereto in the compartments. Additionally, thehold-over mixture which will be in liquid form in pockets I5 will befirst subjected to a freezing temperature at the base portion of thepockets permitting expansion of the liquid at the liquid level.

Various types of hold-over materials may be employed as previouslyexplained, but we preferably employ mixtures having eutectic freezingtemperatures of approximately to l5 degrees Fahrenheit. These mixturesare preferably nonacid and non-alkaline and to prevent electrolysis maycontain a small percentage of chromates. We preferably employ eutecticmixtures of salt and water such as sodium chloride and water, ammoniumnitrate and water, and am-,

monium chloride and water.

The compartments or pockets I5 of the evaporator may be supplied withthe hold-over mixture through openings indicated at I0, Fig. l,

and closed with sealing plugs, a sufficient air partment 46 being filledwith space being provided above the liquid level for expansion.

We contemplate that other arrangements of the passageways may beeffected to accomplish similar results and that our invention is not tobe limited to this particular arrangement other than freezing of thehold-over mixture from the bottom of the evaporator or compartmentupwardly.

We have illustrated in Fig. 6 a modification of our invention whereinthe tray is supported by a generally L-shaped Asheetsteel member,preferably copper-faced as previously described, the upstanding portionbeing secured to the top of the cooling compartment and the horizontallyextending portion being secured to a vertically extending hold-overcompartment generally indicated at 46. The hold-over compartment 46comprises a vertically extending plate 41 suitably affixed to therefrigerator cabinet and a relatively shallow cup member 48 sealinglysecured to plate 41 at peripheral portions, the comhold-over materialthrough an opening 49 suitably sealed by `de tachable plugs.

The lower face of L-shaped element has a grooved plate sealingly securedthereto to form interconnected passages indicated at 50 and 5l, passage5| being connected by a tube 52 to the lowermost passageway 53 of aplurality of passageways formed on the outer side of plate 4l bysealingly securing a grooved plate thereto to form interconnectingpassageways or a continuous passage.

It will now be understood that in this modification refrigerant enterspassageway 50 from the expansion valve and thence passes throughvpassageway 5| effecting freezing of the ice disposed in tray 20, thencepassing downwardly through tube 52 to passageway 53 and thencesuccessively upwardly through passages indicated at 54, 55 to thetopmost passageway 56. The refrigerant may pass from the passageway 56through an outlet connection and conduit leading to the suction side ofthe compressor as previously described. i

In this modification it will be` noted thatthe ice cubes or the like in.tray 20 are flrst frozen and that the hold-over material is frozen fromthe base of the hold-over compartment and upwardly and that at the eametime the air surrounding the evaporator is cooled sufficiently due tothe considerable area of cooling surface presented.

Referring now to Fig. 7, we have shown a further modiflcation of ourinvention somewhat similar to that described in connection with Fig. 6but wherein a greater length of passageway is provided adjacent tray 20and the hold-over compartment is disposed adjacent the top of therefrigerator cabinet. In this modification, the tray 26 is supported byan L-shaped member 60 suitably secured to the top and lateral wallportions of the refrigerator cabinet; and the holdover compartment,generally indicated at 6|, is formed by securing a peripherally flangedplate 62 Vsealingly to the top of the refrigerator cabinet and to theupstanding portion 60. `A continuous refrigerant passageway is providedby a grooved plate secured to the lowerface and outer lateral wall ofelement and to the base ofthe hold-over compartment in the mannerpreviously described.

Refrigerant will enter the passageway successively pass throughpassageways 66,

65 and 61, 68,

3 69, 10, 1I, 12, 13 and so on to passageway 14 and thence, aspreviously described to the compressor. In this .modiflcatlon it will benoted that the ice'cubes or the like contained in tray 20 will be firstfrozen and that the hold-over mixture again is frozen from the baseupwardly while presenting a considerable area for concurrently coolingair within the refrigerator cabinet adjacent the evaporator.

We contemplate that in al1 the modifications described the passagewaysmay be replaced by a continuous coil generally similarly disposed.

Referring now particularly. to Figs. 1-4 inclusive, it will be notedthat the ice cube tray or container shown is of elongated form and toinsure that articles disposed therein will be maintained therein Withoutbeing subjected to undue shock, we provide a metal cover 60 providedwith a depending peripheral flange 8| maintained spaced from thecontainer walls. The cover top contains relatively thick sponge rubber82 maintained by a relatively thin base layer of harder sheet rubber 83.

A shaft 64 is rotatably mounted above cover and is provided witheccentric cover engaging portions 85 whereby when the shaft is rotatedby a handle B6, the cover will be reslliently locked in position on thetray 20 indicated in Fig. 2.

Since the refrigerant system containing my invention is placed in amoving vehicle, both the hold-over solution or solution of brine and thematerial in the container or tray will be in a state of agitation duringthe time that the car is traveling over a road, especially when the caris traveling over an uneven road. Due to such agitation the hold-oversolution or solution of brine and the material in the container as well,will freeze very rapidly and the freezing will take place much fasterthan when said solutions and material in the container are stationarystate.

Although we have shown and described modifications of our invention, wecontemplate that numerous and extensive departures may be made therefromWithout departing from the spirit of our invention and the scope of theappended claims.

Having thus described our invention what we claim is:

1. In a refrigerating system, the combination with an evaporator shell,a container for material to be refrigerated, a compartment containingholdover material, of a continuous conduit therefor formed on theexternal wail of the evaporator shell and compartment so arranged thatrefrigerant passing through the passageway will first subject the baseof the container to a sub-freezing temperature and subsequently subjectthe hold-over mixture to a freezing temperature with maintained in asubstantially the lowermost portions of the hold-over mixture i beingsubjected to refrigerant having greater heat exchange capacity thansuccessively upwardly disposed portions of the,mixture, and thepassageway presenting a considerable surface area contacting airsurrounding the evaporator shell for cooling the same.

2. In a refrigerating system, the combination with a refrigeratorcabinet, an evaporator shell disposed in the cabinet, a tray adapted tocontain ice removably disposed in the evaporator shell, a compartmentcontaining a hold-oven mixture having a eutectic freezing temperaturesubstantially 15 degrees Fahrenheit, of a conduit formed by sealinglysecuring an elementl provided with a continuous groove to the externalwalls of the Y jacent the tray and containing a hold-over mixture havinga eutectic freezing temperature of substantially 15 degrees Fahrenheit,of a conduit secured to the external walls of the compartment and theevaporator shell and following a tortuous path therealong so arrangedthat liquid refrigerant entering said conduit will first subject thetray to a sub-freezing temperature and subsequently freeze the hold-overmixture from the lowermost portion upwardly permitting expansion of theliquid portions of the mixture.

4. In a refrigerating system adapted to use in an automotive vehicle andinoperable for relatively long periods during non-operation of thevehicle, the combination of an evaporator shell, a containerfor materialto be refrigerated'supported thereby, a compartment containing holdovermixture, a continuous conduit formed on the outer walls of theevaporator shell and compartment so arranged that refrigerant passingthrough the conduit will urst cool the container base and subsequentlysubject hold-over mixture to freezing temperature with the lowermostportion of the hold-over mixture Vbeing subjected to refrigerant havinga greater heat exchange capacity than successively upwardly disposedportions of the mixture, and the mixture being adapted to absorb heatfrom the container and air surrounding the compartment duringnon-operating periods of the vehicle.

5. In a refrigerating system adapted to use in an automotive vehicle andinoperable for rela-` tively long periods during non-operation of thevehicle, the combination with a cabinet of an evaporator shell, acontainer for material to be refrigerated supported thereby, acompartment containing hold-over mixture, a continuous conduit formed onthe external walls of the evaporator shell and compartment so arrangedthat refrigerant traversing the conduit will rst cool the base of thecontainer and subsequently subject the mixture to a freezing temperaturewith the lowermost portion of the hold-over mixture being suhiected torefrigerant having a greater heat exchange capacity than successivelyupwardly disposed portions of the mixture, and the major portion of theconduit length being associated with the compartment to effect freezingof the hold-over mixture without a corresponding reduction oftemperature of the air Within the cabinet whereby liquifying of thehold-over mixture during non-operating periods of the vehicle willprovide considerable heat exchange without substantial change in thehold-over mixture tem- Derature.

OSCAR U. ZERK. DANIEL ROLAND VANNEMAN.

